ABSTRACT
Space division multiplexing (SDM), utilizing few-mode fibres or multi-core fibres supporting multiple spatial channels, is under intense investigation as an efficient approach to overcome the capacity limitations of high-speed long-haul transmission systems based on single mode optical fibres. This chapter provides reviews of progress on the implementation of various SDM technologies and presents the latest strategies and trends. The distinguishable spatial data pathways required for SDM are defined either by the particular modes supported by the fibre, or alternatively by orthogonal combinations of these fibre modes. A variety of technologies and approaches are being explored to combine and separate all spatial channels in SDM fibres. Major advances in SDM technology have been made in both few-mode and multi-core fibres. Both of these approaches are being investigated around the globe and a 10-fold increase in overall fibre capacity has already been achieved.
